Magnetic resonance imaging (MRI) provides an image based on information obtained through resonance after exposing an atomic nucleus to a magnetic field. The resonance of an atomic nucleus refers to a phenomenon in which when a specific high frequency radiation is incident in the atomic nucleus magnetized by an external magnetic field, the atomic nucleus in a low energy state is excited to a high energy state by absorbing high frequency energy. The atomic nuclei have different resonance frequencies depending on their type and the resonance is influenced by an intensity of an external magnetic field. There are innumerable atomic nuclei inside a human body and hydrogen atomic nuclei are generally used for magnetic resonance imaging.
In an MRI scanner, it is necessary to generate a radiofrequency (RF) pulse to be applied to an object during scanning. In general, a linear amplifier with kilowatt (kW) output power is used in the MRI scanner. In general, low efficiency of such a linear amplifier requires a cooling system, which increases a volume of the MRI scanner. In most cases, the amplifier is located outside a scanner room and away from a transmission coil, thereby additionally reducing efficiency and increasing overall cost of a system.
Therefore, there is a need for an MRI scanner that uses an amplifier having higher efficiency.